WARNING Front strut lubrication LHM contamination risk

[ellevie]

WARNING Front strut lubrication LHM contamination risk

http://www.bxclub.co.uk/diy/struts/

The BX DIY link above proposes a cure for groaning front struts by sucking some LHM in through the vent & leakback rubber pipes located on the side of the struts behind the front wheels. However when I did this, instead of just putting the pipes back on as prescribed, I pumped the fluid back out into the small container to have a look at it and discovered that it was so dirty as to be almost pitch black.

If you follow this procedure you run the risk of serious LHM contamination and possible damage to the hydraulic components. Citroen attach great importance to keeping the LHM scrupulously clean.

A safer and more immediate cure for groaning struts is to squirt some 3&1 oil in through the small finger sized hole in the rubber gaitor at the top of the strut within the engine compartment. If you look through the hole you should be able to see the shiny silver surface of the top of the strut --- try and squirt the oil directly on to this silver surface. Then push the front suspension up and down a few times to work the oil in.

[Way2go]

Your proposal does not do the same thing Ellevie but has a possible benefit to be done as well as.

The link info relates to drawing LHM in where LHM doesnt live and the groaning is probably more relieved by cleaning the gunge and residue off the empty travel beneath the piston than by lubricating it. System LHM only comes this way as leak-past and what you put in cannot rise into the system as there are no ports for it to do so.

If you found that much gunge inside there may be a case for you to do it more than once until the gunge is predominantly washed out and the lhm runs clean before reattaching the (drained) return (Leak-off) pipes.

[ken newbold]

Any LHM discharged through the return pipes does go back to the reservoir through the the return system and could cause more problems if it's contaminated.

[charlotte001]

Ill do it with 3 in 1 then

[kermit the frog]

The only simle way of getting rid of contanination is to lower the suspension open the pressure return valve 1/4 turn to drain all system pressure back into the LHM tank remove and drain the tank clean ot the tank and the filters.
(There are two the large return filter and the conical pickup filter.)
Also the level sesor can be removed and cleaned by turning the top where the connections for the warning light are.(1/4 turn anti clockwise)
you can carefully remove the plastic cap at the bottom of the sensor tube with a small pick(be carefull not to break the locating slots in the tube)

(Don't forget the plastic disc in the bottom of the tank)
This seperates the water contamination from the LHM
Refit the tank top up with new LHM tighten pressure return valve start engine raise suspension to highest level and drop to low a few times.
check level.
Run car for a week to run fluid round system and repeat this will remove most of the system gunge to the tank.
This is an easy alternative to hydraflush and i have used it sucsessfully on my BX.

Regards Kermit

[MULLEY]

Er, i'm a bit confused by this contamination lark, the struts are already full of crappy lhm, so isnt this already in the system? So surely using the technique as described in the diy section is a good thing as you will be cleaning out the strut & therefore removing all the contaminated lhm from the entire system?

Or, is the contaminated lhm in the strut, does it just stay in the strut? but when disturbed it could get into the rest of the lhm system?

[kermit the frog]

I agree with you on the DIY cleaning step i was mearly trying to give some way of cleaning the remainder of the system as all hydraulic systems work at their most efficient when the are clean.

sorry if i was getting you confused it was not my intention.

Regards Kermit

[MULLEY]

No worries Kermit, just wanted to double check that my thought process & the diy section wasnt adding any extra grunge to the system overall...

Isnt using hydraflush better than the lhm method you've desribed? not criticising, just wanted to know as i think lhm works out slightly cheaper to do it your way?

I also thought that the brakes had to be bled as well to ensure every last bit of crud is out?

Sorry a billion questions for you or anyone else reading this thread

[kermit the frog]

Oop's sorry yes the brakes should be bled out.
But only to refresh the fluid in the calipers as this fliud although part of the same system does not circulate around the system.
On an ABS car the LHM does flow through the ABS valve block back to the tank when the ABS is working.
But the brakes themselves are at the ends of pipes no return.

regards Kermit

[cauchoiskev]

The only simle way of getting rid of contanination is to lower the suspension open the pressure return valve 1/4 turn to drain all system pressure back into the LHM tank remove and drain the tank clean ot the tank and the filters.

If your LHM is less than two years old, you can clean it even more cheaply than that. I have found that the dirt - fine silt - always accumulates underneath the plastic disc, leaving the LHM above it quite clean (in a well-maintained car).

So from time to time, I siphon off the LHM down to the level of the plastic disc, then chuck away what's left underneath it (about a quarter of a litre), and stick the old LHM back in and top it up with new. Works wonders when the steering gets a bit heavy.

And in case you're wondering, yes, I am Scottish .

[kermit the frog]

This is a very sound piece of advice .
But only as you say if the LHM is under 2 years old and the car is well maintained.
But as we know if you buy a BX there is a good chance that it is the part of the car that has received the least attention.

Especially if it hasn't seen a citroen main dealer or specialist in a while.
Afterall the suspension is the best bit when it's working well and all the other bits that use this pressurised system will all benifit from a good clean out.
And LHM is still cheaper than another car.

Regards Kermit

[AndersDK]

I dont see any problems in lubing up the struts as pr instructions found in the link submitted first up.

I do however find a serious problem going the old and thoughtless way using the "LHM in the hole" trick. Been around for ages, this trick is still as wrong and silly as it can be :

any low viscosity (i.e. light flowing) oil, being it LHM, 3-in-1, WD40, 0w40 synt oil or whatever, will silently but very securely seep down outside the strut and most likely lube up your brakes.
The consequences are obvious, even if you think first off its nice with silent brakes.
The strut is lubed for a short while, then it runs dry again, because this way of lubing has no means of maintaining the lubing - like inside an engine with low viscosity oils where you have the constant flow of oil.

Its a thoughtless and silly way of thinking how things works.

The lubing procedure found in the link is much more complex than just a single one off strut lubing. What it actually does is to soak the internal felt washer with LHM besides wetting all the internals of the strut. The felt washer is responsible for maintaining the LHM film on the strut, which is then lubed for a very long time.
The idea is to set up and constantly maintain an oil film on the strut.

Any contamination of the LHM this way is caught by the return filter in the reservoir, and is in no way more serious than any other contamination already occurring by the functioning of the system.
Most serious contamination of the LHM is done by the breathing in bellows and the reservoir, as then humid and dusty air gets into these cavities ...

[mtbxathena]

Evening all. Just spent a couple of hours lubricating my TZD front struts as per the BX DIY link. I put the 2 ends of the strut pipes into a full clear bottle of LHM and worked the strut up and down the full length of its travel by placing a 4 foot piece of decking under the disc. After just 3 strokes the LHM in the bottom of the bottle was very dark so I continued using this method until the LHM was running clear, in my case about 12 strokes per side. As the BX is my only form of transport I shall run it for a week and check to see if the fluid from each strut is still clear. PS. The struts are a lot quieter already. Regards, Mick.

[charlotte001]

I'm going to read the rest of the replies later but I'm lubricated my groaning strutts by the method suggested and not taking pipes off. I'm going to give the car a total LHM flush this week as no doubt the fluid has been there for a good while

Probably asked does anyone know if the refered to kits are still available so I can take the strutt off and rebuild it so I know the condition.

Charlotte001

[cauchoiskev]

There is no single kit for the struts, rather two kits + the bush + the cylinder.

To rebuild them as new costs about 200 quid per strut.

However, I changed only the teflon joint and o-ring (about 4 quid), and the result was perfectly satisfactory i.e. it stopped the leaking. The cylinder and bush both seemed fine - these struts have 300000km, and don't creak.

This is not an easy job. You need strong arms and a means of getting the bush off (very big stilson or simililar + vice).